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The Fat Fight Goes On

By John Tierney July 24, 2008 12:18 pmJuly 24, 2008 12:18 pm

Many readers took issue with the good news on saturated fat, as I described Gary Taubes’s take on a new Israeli study that compared an Atkins-like low-carb diet with other diets. Mr. Taubes, the author of “Good Calories, Bad Calories,” noted that the people eating the low-carb diet ate more saturated fat than the other dieters but ended up with an improved cholesterol profile. He called it perhaps the best evidence yet that saturated fat has been wrongly condemned by the American Heart Association and the federal government.

Some readers argued that there wasn’t that much difference in saturated-fat consumption among the dieters. Saturated fat constituted a little less than 10 percent of the calories consumed by the people on the Mediterranean and A.H.A. low-fat diets; it constituted about 12.5 percent of the low-carb dieters’ calories. Some critics said that’s a difference of only 2.5 percentage points; others noted that it represents an increase of 25 percent. Both, of course, are right.

Here’s Mr. Taubes’s reply:

In an ideal world, it would be great to have significantly larger differences in saturated fat content. It would also be great to have studies that looked at heart disease endpoints and, ideally, overall mortality. That’s what I argued for in the epilogue of “Good Calories, Bad Calories,” while acknowledging that studies of health outcomes (rather than just change in cholesterol numbers and weight) would cost hundreds of millions of dollars, if not more. It’s unlikely they’ll ever be done. And if they are done, they would take years to plan and the better part of a decade to accumulate enough hard endpoints, as they’re known in the lingo — heart attacks, deaths, new cases of cancer, etc. — to generate statistically significant results. I still think they’re worth it, but the folks at the National Institutes of Health do not, or at least not yet.

The point I was making is that all the relevant diet trials done in the last decade — randomized controlled trials comparing Atkins-like low-carb diets to AHA low-fat, calorie-restricted diets — of which there are now more than half a dozen, have observed the same result., In each one, LDL on the two diets was a virtual wash and cholesterol profiles (total/HDL) showed greater improvement on the Atkins diet. When the trial looked at blood pressure, that improved significantly on the higher fat, lower carb diet. In this Israeli study, they looked at markers of inflammation — same story.

What we have to keep in mind here is that nutrition is a science (or at least should be) and science is about generating hypotheses, making predictions from our hypotheses, and then seeing if they hold true. The relevant hypothesis here — i.e., what we’ve believed for the past 30-odd years — is that saturated fat causes heart disease by elevating either total cholesterol or LDL cholesterol, specifically. So our prediction is that the diet with the higher saturated fat content will have a relatively deleterious effect on cholesterol. We do the test; we repeat it a half dozen times in different populations. Each time it fails to confirm our prediction. So maybe the hypothesis is wrong. That seems like a reasonable conclusion. No one is proving anything here — as some of your respondents like to decry — we’re just looking at the evidence and trying to decide which hypotheses it supports and which it tends to refute.

The knee-jerk response — as exemplified by quite a few respondents — is to assume that sometime in the not-too-distant past, maybe the 1960s or 1970s, before this low-fat dogma set in, such trials, or far better trials, were done and found the opposite — that the higher the saturated fat in the diet, the lower the cholesterol and the better the cholesterol profile. Or the higher the saturated fat, the greater the mortality. But that’s simply not the case, as I point out in my book. In fact, I’ve been criticized (by Gina Kolata, among others) for going on and on in the book about all the different studies. But I did so precisely because I didn’t want to be accused of cherry picking the data. (I was anyway, but that’s just the nature of this business.) When Ancel Keys, for instance, reported in the 1950s reported that saturated fats raised total cholesterol, which they did in his studies, he based it on comparisons of butter fat to polyunsaturated oils in studies that lasted only two to nine weeks. (He also reported, curiously enough, that the saturated fats had no significant effect on LDL.)

These latest trials just happen to be the best data we have on the long-term effects of saturated fat in the diet, and the best data we have says that more saturated fat is better than less. It may be true that if we lowered saturated fat further — say to 7 % of all calories as the American Heart Association is now recommending — or total fat down to 10 percent, as Dean Ornish argues, or raised saturated fat to 20 percent of calories, as Keys did, that we’d see a different result, but that’s just another hypothesis. The trials haven’t been done to test it. It’s also hard to imagine why a small decrease in saturated fat would be deleterious, but a larger decrease would be beneficial.

It’s also true that I don’t think that LDL is a particularly meaningful predictor of heart disease risk, and I think total cholesterol is meaningless (based on the evidence that I recount in the book). But the point is that the AHA and the National Cholesterol Education Program and the authorities at the National Heart, Lung and Blood Institute do think LDL is meaningful, and that’s the basis by which they have always recommended low-saturated-fat diets. They also think that total cholesterol/HDL is the single best predictor of heart disease risk, so by their assessment, more saturated fat is better than less. I think the best predictors of risk regarding cholesterol profiles are HDL and the size and density of the LDL particles themselves, and maybe measurements of a protein known as ApoB (the protein component of the LDL particle itself) — and the existing diet trials in those cases also suggest that saturated fats are at worst harmless and perhaps even beneficial.

Last point, the funding. It’s true that the study was financed by the Atkins Foundation, but to assume that the researchers went out and falsified their findings or twisted their observations to satisfy the source of funding is naive. Regrettably, the only institutions that will finance clinical trials, for the most part, are those that stand to gain from the results. That’s why the pharmaceutical industry finances drug trials. It would be nice if the government financed all these trials, but they don’t. So it’s up to the Atkins Foundation and any other organizations that might hold similar beliefs. In this case, the Atkins-funded diet trial observed the exact same results as similar NIH-funded diet trials.

Worth noting here is that the NIH has also spent $5 million recently for a large (300+ subjects, two-year-long) Atkins vs. AHA low-fat diet trial. This is a larger and longer version of a pilot trial that observed results similar to the Israeli trial. To my knowledge, it’s the largest diet/weight trial the NIH has ever funded. The principal investigator was Gary Foster of Temple University, currently the president of the Obesity Society, which is to obesity these days what the American Heart Association is to heart disease. In February of 2007, Dr. Foster told me the researchers had “completed the final 2 year assessments on most but not all” of their subjects. This week he told me that a paper on the results is “in the peer review process” and that “journal policies prevent me from saying more than that.” It would be nice to see those results, and we can only hope they’ll be published soon.

Any Lab reader care to venture a prediction on the results of the NIH study? (The best prophet will be duly celebrated here when the results comes out.) Or do you have any other thoughts on this issue?

Predictions: The NIH results will “decriminalize” the Atkins diet. In whatever journal the results are published, there will be at least one commentary talking about flaws in the study and the need to explore the issue more (and oh yes, while further study continues, we should still follow the “tried and true” low-fat AHA guidelines).

OK, so I’m saying this as a young, healthy, active male, and I’ll admit up front to a degree of naive overconfidence regarding health issues. With that being said, though, I have to wonder: what is this particularly American fetish over ‘dieting’ and eating in extremes of any kind? And how is it that you, Tierney, are willing to oblige the marketers and progenitors, the hawkers of books and pre-packaged, points-weighted meal sellers by perpetuating this fantasy debate over what’s ‘healthy’ and what’s bad, or wrong, or evil in food?

All my life I’ve watched the women in my family submit themselves to these awful, lopsided, costly ‘diets’ as well as consuming countless products proclaiming their own versions of saccharine healthiness. And to what end? Sure, they may lose a few pounds here, or a score there, but in the end they’re essentially the same as they were to begin with — just give them a few months to adjust from whatever bodily shock they’ve just been through.

Can anyone tell me what’s so essentially wrong with keeping meat consumption low, eating plenty of vegetables and fruits (not just corn and legumes), and making sure you buy bread with whole grains? Do that, exercise for 30 minutes a day, and stop stressing yourself to death over what you eat! You’ll probably save money in the long run, anyway.

Bull. Utter Bull. When will the public stop trying to blame their waistlines on some mythical nutrient (or lack thereof) and realize that food…real actual food that does not come from a box, is the only thing you should eat. Eat Food. Not Much. Mostly Plants. How hard is that to recognize?

The Atkins Diet has only helped me. I eat less, get hungry less often, and have lost the weight I needed to lose. Many folks don’t realize that the Atkins Diet is not only about what to eat. One also needs to exercise, for example. Plus, there is a strict step-by-step structure to follow for the first months on the plan. It gets easier over time, with the first few weeks being the toughest. If those who try the diet were to follow the plan “to the letter”, from beginning to end, we’d hear even more success stories.

I predict – if the NIH study confirms that Atkins is ok – a large number of people will somehow blame the results on a a conspiracy within the Bush Administration. And, I’ll bet Tierney dinner at Peter Luger’s, that at least 50% of them will be from Northern California or Colorado.

John: Thanks for the offer. But after all the anti-Bush comments posted here on topics that have nothing to do with the White House, I wouldn’t bet against you on this one.

Another smart perspective from Taubes. I’m eager to hear about the results of the NIH study, and I’m guessing the low-fat diet will come out behind. There’s a noteworthy amount of evidence already in favor of a diet rich in natural saturated fats. Lower metabolic risk factors, less obesity, intake of fat-soluble vitamins, lots of good butter… sounds far preferable to me than skim milk and margarine.

I’m surprised there has been no mention of genetics here. Therefore one diet is not the best for everyone. I’ve tried all various diets, but now I don’t think much about dieting (this is a good thing – try it!) Did you know that the minute you pop out of the womb your arteries begin to harden. I agree with TomD, don’t eat processed foods, make your meals yourself and you’ll be fine. Moderation is a great thing! Just some random things to think about. LG

I milk my own goats, and occasionally indulge in cabrito. I till my own earth–at this time in the Texas summer there are tomatoes, okra, luffa squash, zipper peas, all different kinds of herbals, and a plethora of basil.

This fall, there will be greens and turnips and beets.

Work your own garden, husband animals that you love, and you will never carry around those extra pounds that strain every system in your body.

Ah, yet another one study wonder. A two year study with only 322 subjects does not a significant statistic make.

If you ask a smoker whether he smokes, he’ll say ‘no’ for smokers are pariahs. If you ask an overweight/obese person what they eat, they’ll mislead you and blame their condition on genetics.

When it comes to excess weight portions and activity levels are the two key elements. When I go to a restaurant I invariably leave with a large doggie bag that will last me for several days — well, unless the dogs actually get some.

I agree with TomD — with the exception of eating meat. I probably eat more meat than he does. After cooking for our family for 40 years, I am frankly tired of being in the kitchen. Rather than grocery shopping, I market, buying what appeals to me, in season and inexpensive. While it’s been difficult to cook for two rather than six (plus all their friends), I’m getting better at it.

My prediction? Yet another diet fad based on unsubstantiated ‘facts.’ We’ll see more diets like the cabbage soup diet, South Beach, Mediterranean, whatever. Books will sell as folx look for the magic bullet.

I wonder if the potential confounder of alcohol consumption was taken into consideration. Consumption of same leads to lack of impulse control. Hours of television watched per day

In addition, one must consider the factor of publication bias. NEJM, JAMA, BMJ count on notoriety to sell ads. A study that concludes that you can eat whatever you want as long as you don’t eat too much will never be published. Ain’t sexy enough. Far too few putative ‘science’ reporters read beyond the abstract/conclusion. They know naught of RRs, CIs and ‘n.’ One notable exception is Gina Kolata of this newspaper. In short, aside from a small handful of people who understand research and statistics, ‘if it scares, it airs.’ If it sounds unbelievably wonderful, it hits the front page of the health section. If it makes enough noise (think NASA’s Jim Hansen and his ‘hockey stick’ model), refuted by over 10K fine scientists, it runs above the fold.

Sorry for the long post. My field of work is researching research and I get a bit testy.

Prediction: Atkins wins. Coverage is minimal. Coverage declares that AHA diet works, as proven in study. Possibly point to what study participants do as “not Atkins” despite having not much understanding of what that is (Kolata is a key offender who confuses the 14 day Induction with the entire Atkins Diet… others at the Times are similarly confused, or conflicted, or invested or whatever).

A close read of the results will show:
1- People on the Low Carb diet lost more weight.
2- Had better compliance.
3- Had more improvement to lipid profiles.
4- Greater improvement to blood pressure.
5- Better blood sugar numbers.
6- lower inflammation levels.
7- No acid reflux
8- More energy.
9- And basically do better in whatever they want to measure.

I’ll bet the findings will be favorable towards the low carb diet but there will be loads of spinning, as per normal, by the researchers in the conclusions. The press will report it as favorable for low fat, no matter what the results are. :p

The NEJM study evaluated the effects of a workplace-based dietary intervention. To me, it seems that one of its most important strengths is to show that such a focus by an employer can make a difference. Contrast the health support of the employer in the study with that seen in most American workplaces, where a dingy staff room offers two or three vending machines crammed with preservative-rich snacks that aren’t even on the same dietary map as the foods in any of the three groups in the study.

I’ve always seen the AHA recommendations as a useful way to do something that most Americans don’t do: monitor and limit what you eat, and eat less of foods that our culture encourages you to gorge on. In that context, following any of the three diets would be more healthful than what most of us do now. Surely a more moderate approach would bring health benefits to us all.

In the Israeli study, the three treatment groups are similar in ways that in themselves promote health. First, these are “diets” To some extent, just having your food intake monitored is likely to reduce gorging and lead to weight loss. Second, all diets were consumed at midday- the time of the main meal in Israel. Late-night eating has been shown to adversely affect weight. Third, even the lo-carb diet participants were instructed to choose vegetarian sources of fat and protein whenever possible, so it wasn’t as if they were guzzling down slabs of beef and pork. Fourth, all groups lost weight and seemed to maintain the weight loss, something that’s hard to do for many Americans–again, support for monitoring as an intervention in itself.

The fasting plasma glucose results in this study for diabetic participants should not be ignored. They showed significant decreases in people assigned to the Mediterranean diet. By contrast, fasting glucose levels increased with the low-fat diet. Glycosylated Hb1Ac decreased the most in the low-carb group, the only group with a significant decrease, and least in the low-fat group.

It seems to me like the biggest mistake is to become fanatical about any of this. Saying “total cholesterol is meaningless”, or that “more saturated fat is better than less”, to quote Gary Taube, may be true to the extent that the evidence doesn’t support a tight link between cholesterol levels and heart disease outcomes, but since patients in real life usually have multiple and related problems–obesity, high blood sugar, hypertension–it would be hard for any physician to encourage an overweight, hypertensive, sedentary 50-ish male to keep up his Supersized high-animal-fat diet. Most people don’t think in gray about their diets, which is one reason fad diets catch on. AHA, Mediterranean, or Atkins–in the Israeli study, everyone was better off according to most–but not all-of the health indicators. I vote for moderation in all things, including even olive oil and veggies.

Predictions:
1) The study will show (again) that controlled carbohydrate nutrition results in superior cardiovascular health markers as well as weight loss.

2) The medical and scientific community will be “surprised” that such an “unhealthy diet” could have such better results.

3) Dean Ornish and the PCRM crew will publish rebuttals claiming that obviously these results are only because the low-fat diet was not low-fat enough. Various vegan groups will admonish people to read The China Study so they can know just how “dangerous” meat based diets really are. Katie Couric will ask a talking nutritional head on the national nightly news that “this latest study results aside, in the end its really about portion control, right?”. The talking head will nod appropriately and enthusiastically.

4) Various “authorities” will publish statements to the public warning that the long term effects on health of the Atkins diet are not known, so no one should start cutting carbs thinking its actually good for them.

5) The USDA will revise its food pyramid, emphasizing even more whole grains.

6) and once again we’ll inch ever so slowly toward the medical community understanding that eating low-carb is best for optimal health…

Last point, the funding. It’s true that the study was financed by the Atkins Foundation, but to assume that the researchers went out and falsified their findings or twisted their observations to satisfy the source of funding is naive.

That is perhaps the most inverted use of a term (here “naive”) that I have seen in a while!

A perfect illustration, I think, of the dangers of making grand inferences on the basis of inadequate data. World, do some studies that separate variables or cover more scenarios, and then get back to me. Until then, diet pronouncements will be little more than faddism, whoever is making them.

I wrote earlier at length about the importance of outcome measurement, and I am glad to see Mr Taubes respond here, that it is considered too expensive.

However, we are still spending money on medical research. How much of that goes to research related to the cholesterol theory, and how much to prevention of the half of heart attacks in people with nonrisky lipid levels (no matter the diet)? It seems to me if the latter is much smaller than the former, we ought to redirect it toward something that could make a big difference in prevention rather than later expensive treatment.

Again, it seems to me that the difference in these studies between low-fat or low-carb is too small to be so important to spend money on, we should spread our research money bets on other things such as inflammation or newer ideas such as what tips plaques into blockages.

Stopping cigarette smoking I think has had the most impact in such prevention of cardiovascular morbidity and mortality. We should consider a similar big push to lower salt intake to control blood pressure, as Japan has done, as our population ages like theirs. This would involve some investment in replacing cheap salt in preserved foods and developing recipes to make low-salt food tasty and preferable. I think this low-salt change in diet might have a much greater, and more immediate, impact on cardiovascular health than any tinkering with low-fat or low-carb to affect lipid levels.

There is a strong possibility that diet interacts with genetic factors such as expressed proteins to cause disease (as some African Americans are said to be more sensitive to salt on blood pressure). This might be a good area to spend money on more research as the technology develops to understand it.

On a serious note, the media response to last week’s NEJM article was much more positive than the response to the first NEJM articles of 2003, or even the JAMA papers 2006 and 2007. I think that is a reflection of the change of the expert opinion due to a growing evidence base for low-carb in the published literature. Did a major obesity/nutrition researcher do an interview which criticized the study (other than Bob Eckel from AHA)?

Gary Taubes has made the point over and over again that the public health establishment is all too often completely unwilling to be convinced by the evidence. Despite the fact that the superiority of low carbohydrate diets for improving the lipid profile has now been replicated in several studies, the cardiology community, uninterested in evidence and clinging desperately to a paradigm that is about to explode, continues to make statements like these:

From the American College of Cardiology Website

“Perspective: The results are similar to many reported in free-living moderately obese adults and those with insulin resistance. The message for physicians, dietitians, and their patients is that the best choice is a caloric-restricted diet chosen by the patient. We try to promote the Mediterranean diet in CHD and the metabolic syndrome, but give the patient the choice to begin with a low-carbohydrate diet to jump start weight loss and enhance initial compliance, and transition to the Mediterranean diet over time. Melvyn Rubenfire, M.D., F.A.C.C.”

From the American Heart Association Website

“…Just as importantly, the 2006 recommendations focus on what people should eat more of — fruits, vegetables, low-fat dairy products, lean-meats, poultry and fish twice a week. These recommendations were developed by internationally recognized experts, who based their recommendations on hundreds of published studies that looked at the relationship between what people eat and the development of heart disease and stroke.

The diet identified as Mediterranean in the study was high in fiber and vegetables and low in red meat (a major source of saturated fat), with no more than 35 percent of total calories coming from fat. This pattern reflects the current recommendations from the American Heart Association.

Multiple studies have shown that diets high in saturated and trans fats are strongly associated with the development of heart disease, and that diets rich in fruits, vegetables and whole grains are strongly associated with a lower risk of heart disease.

Robert H. Eckel, M.D., a former president of the American Heart Association and a professor of medicine at the University of Colorado Denver School of Medicine cautions the public about jumping to conclusions about the results of the Israeli study.

‘Although the people who ate the low carbohydrate/high protein diet lost more weight, it is crucial to consider what diets high in saturated fats might do to your blood vessels and heart over time. The scientific evidence strongly indicates that this type of diet could put people at higher risk of developing heart disease.’”

It appears that the cardiology community no longer believes in the scientific method but instead operates like a cult. They believe what they believe because they believe it; evidence be damned!

Will someone please remind me why the American tax payer invests $100 billion in biomedical research through the NIH, if the results of trials that the NIH supports are routinely ignored?

I think the resistance to the scientific data (Atkins is best) is more about guilt than the potential to lose face or lose money. It’s the idea that you’ve been (innocently) leading people to their graves for years. No nutritionist, scientist, or journalist wants to face up to that, even though by now it’s clear that the food pyramid/low fat diet is horrible for everyone (see obesity rates) and that Atkins can improve many people’s health immesurably. (I’ve lost 30 lbs on Atkins. My BMI is now 20.)

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About

John Tierney always wanted to be a scientist but went into journalism because its peer-review process was a great deal easier to sneak through. Now a columnist for the Science Times section, Tierney previously wrote columns for the Op-Ed page, the Metro section and the Times Magazine. Before that he covered science for magazines like Discover, Hippocrates and Science 86.

With your help, he's using TierneyLab to check out new research and rethink conventional wisdom about science and society. The Lab's work is guided by two founding principles:

Just because an idea appeals to a lot of people doesn't mean it's wrong.

But that's a good working theory.

Comments and suggestions are welcome, particularly from researchers with new findings. E-mail tierneylab@nytimes.com.